Dry mechanical seal vacuum pump

Abstract

An embodiment of the present invention provides a dry mechanical seal vacuum pump, which relates to the technical field of vacuum pumps. The dry mechanical seal vacuum pump includes a bearing, a rotor, an end cover, and a dry mechanical seal device. The bearing, the end cover, and the dry mechanical seal device are all sleeved on the end of the rotor, and the dry mechanical seal device is clamped between the bearing and the end cover; the dry mechanical seal device includes a dynamic ring seal assembly and a static ring seal assembly. The dynamic ring seal assembly is sleeved on the rotor and rotates synchronously with the rotor. The static ring seal assembly is connected to the end cover, and the end face of the dynamic ring seal assembly and the end face of the static ring seal assembly form a pair of friction pairs. By adopting the dry mechanical seal device, the vacuum degree of the dry vacuum pump can be improved, the sealing performance of the pump cavity and the bearing box can be increased, thereby improving the service life of the pump and improving the process environment of the upstream equipment, avoiding oil pollution of the process gas, and at the same time, preventing dust in the pump cavity from entering the bearing box and damaging the bearing.

Description

Technical Field

[0001] The present invention relates to the technical field of vacuum pumps, and more particularly, to a dry mechanical seal vacuum pump. Background Art

[0002] With the development of the economy and the progress of society, the equipment processes in the photovoltaic semiconductor industry have increasingly higher requirements for the vacuum degree and the cleanliness of the vacuum environment of dry vacuum pumps. The corrosiveness and dust of process gases are increasing, which greatly challenges the performance of vacuum pumps. How to effectively block the process gases and dust from entering the bearing box to damage the bearings, and prevent the oil in the bearing box from entering the vacuum pump cavity to damage the vacuum degree and upstream equipment has become a key problem for dry vacuum pumps.

[0003] Existing sealing technologies mainly rely on lip seals and labyrinth seals to isolate the process medium and the bearing box. However, they are both non-contact seals with general sealing ability and continuous leakage. It can be seen that the sealing effects of labyrinth seals and lip seals are poor and cannot meet the increasingly demanding process conditions. The specific defects are as follows:

[0004] 1. They are non-contact seals with poor sealing effects;

[0005] 2. The service life of lip seals is short and replacement is troublesome;

[0006] 3. They have poor resistance to high temperature and strong corrosiveness;

[0007] 4. The lips of lip seals are easily worn quickly, and residues are likely to enter the pump cavity, causing harm to the pump cavity. Summary of the Invention

[0008] The objectives of the present invention include providing a dry mechanical seal vacuum pump, which can improve the vacuum degree of the dry vacuum pump, enhance the sealing performance of the pump cavity and the bearing box, thereby increasing the service life of the pump and improving the process environment of upstream equipment, and avoiding oil pollution of process gases.

[0009] The embodiments of the present invention can be implemented as follows:

[0010] In a first aspect, the present invention provides a dry mechanical seal vacuum pump. The dry mechanical seal vacuum pump includes a bearing, a rotor, an end cover, and a dry mechanical seal device. The bearing, the end cover, and the dry mechanical seal device are all sleeved on the end of the rotor, and the dry mechanical seal device is clamped between the bearing and the end cover;

[0011] The dry mechanical seal device includes a dynamic ring seal assembly and a static ring seal assembly. The dynamic ring seal assembly is sleeved on the rotor and rotates synchronously with the rotor. The static ring seal assembly is connected to the end cover, and the end faces of the dynamic ring seal assembly and the static ring seal assembly form a pair of friction pairs.

[0012] The beneficial effects of the dry mechanical seal vacuum pump provided by the embodiments of the present invention include:

[0013] 1. The dry mechanical seal device adopts contact sealing between the dynamic ring seal assembly and the static ring seal assembly, with good sealing effect and very small leakage.

[0014] 2. By adopting the dry mechanical seal device, it has a long service life and reduces the time cost of shutdown maintenance.

[0015] 3. The dry mechanical seal device has good high-temperature and corrosion resistance, is suitable for use in harsh vacuum pumps, and significantly improves the performance of the vacuum pump.

[0016] 4. By adopting the dry mechanical seal device, the sealing contact surface can be made smaller, the friction between them is smaller, heat generation is reduced, and it has good sealing performance and a long service life.

[0017] 5. There is no need to use liquid as the liquid film of the sealing contact surface for sealing, avoiding the entry of liquid into the cavity and damaging the process medium.

[0018] In an alternative embodiment, the dry mechanical seal vacuum pump further includes a spring, which is clamped between the end cover and the static ring seal assembly, and the spring is used to push the static ring seal assembly towards the dynamic ring seal assembly.

[0019] In this way, the spring is used to push the static ring seal assembly towards the dynamic ring seal assembly, ensuring that the static ring seal assembly and the dynamic ring seal assembly have a large relative extrusion force, and ensuring that the sealing performance of the sealing contact surface formed by the two is good.

[0020] In an alternative embodiment, the elastic force of the spring on the static ring seal assembly is: 25N - 30N.

[0021] In this way, through repeated testing and calculation, when the spring maintains an elastic force of 25N - 30N, it not only ensures good sealing performance of the sealing contact surface, but also ensures moderate friction between the static ring seal assembly and the dynamic ring seal assembly, and there will be no situation of overheating and damage too quickly.

[0022] In an alternative embodiment, the static ring seal assembly includes a static ring, a connecting pin, a static ring seat, and an anti-rotation pin. The end face of the static ring forms a friction pair with the end face of the dynamic ring seal assembly. The static ring is connected to the static ring seat through the connecting pin, and the static ring seat is connected to the end cover through the anti-rotation pin.

[0023] In this way, the structural form of the static ring seal assembly is simple and it is convenient for loading and unloading.

[0024] In an alternative embodiment, the end face of the static ring for contacting the dynamic ring seal assembly is a circular ring, and the width of the circular ring is: 2mm - 2.5mm.

[0025] In this way, the sealing contact surface is a circular ring with a width of 2mm to 2.5mm. The sealing performance is good, the friction is moderate, and there will be no damage due to excessive heating.

[0026] In an optional embodiment, the stationary ring sealing assembly further includes a stationary ring O-ring and a stationary ring seat O-ring, the stationary ring O-ring is clamped between the stationary ring and the stationary ring seat, and the stationary ring seat O-ring is clamped between the stationary ring seat and the end cover.

[0027] In this way, the stationary ring O-ring can ensure the sealing ability between the stationary ring and the stationary ring seat, and the stationary ring seat O-ring can ensure the sealing ability between the stationary ring seat and the end cover.

[0028] In an optional embodiment, the dynamic ring sealing assembly includes a dynamic ring seat and a dynamic ring ring. The dynamic ring seat is sleeved on the rotor, and the dynamic ring ring is installed on the dynamic ring seat. A first dynamic ring O-ring is arranged between the outer circumferential surface of the dynamic ring seat and the inner circumferential surface of the dynamic ring ring, and a second dynamic ring O-ring is arranged between the end face of the dynamic ring seat and the end face of the dynamic ring ring.

[0029] In this way, the dynamic ring sealing assembly has a simple structure and is easy to load and unload. The first dynamic ring O-ring can ensure the verticality of the friction end face of the dynamic ring, and the second dynamic ring O-ring can ensure the sealing ability between the dynamic ring seat and the dynamic ring.

[0030] In an optional embodiment, the dry mechanical seal vacuum pump further includes a clamping ring and a throttling ring, wherein the clamping ring is clamped on the end cover, and the throttling ring abuts against the end cover and the clamping ring and is located at the periphery of the dynamic ring seal assembly.

[0031] In this way, the throttling ring is arranged between the end cover and the dynamic ring seal assembly to reduce the gap between the end cover and the dynamic ring seal assembly, thereby preventing the lubricating oil of the bearing from passing through the gap between the end cover and the dynamic ring seal assembly and affecting the working performance of the rotor.

[0032] In an optional embodiment, a first purge channel is provided on the rotor, an inlet of the first purge channel is located on the end face of the rotor, an outlet of the first purge channel is located on the outer circumferential surface of the rotor and directly opposite the dynamic ring sealing assembly, a through hole connected to the first purge channel is provided on the dynamic ring sealing assembly, and an air flow is blown toward the space between the dynamic ring sealing assembly and the static ring sealing assembly through the through hole.

[0033] In this way, by blowing a purge airflow, such as nitrogen, into the first purge channel, impurities between the dynamic ring seal assembly and the static ring seal assembly can be blown out of the pump body, thereby ensuring stable operation of various internal parts.

[0034] In an alternative embodiment, a second purge channel is provided in the end cap. The inlet of the second purge channel is located on the outer surface of the end cap, and the outlet of the second purge channel is located on the inner surface of the end cap. The air flow blows through the second purge channel towards the periphery of the dynamic seal assembly and flows away from the static seal assembly, preventing the lubricating oil on the bearing from flowing towards the direction where the static seal assembly is located.

[0035] In this way, by blowing the purge air flow, such as nitrogen, through the second purge channel, the air flow can be made to flow towards the bearing, preventing the lubricating oil on the bearing from flowing towards the direction where the static seal assembly is located. At the same time, dust in the pump chamber is prevented from entering the bearing housing and damaging the bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0037] Figure 1 It is a schematic structural diagram of a dry mechanical seal vacuum pump provided by an embodiment of the present invention.

[0038] Reference numerals: 100 - dry mechanical seal vacuum pump; 1 - bearing; 2 - rotor; 21 - first purge channel; 3 - end cap; 31 - second purge channel; 4 - spring; 5 - snap ring; 6 - throttle ring; 7 - dry mechanical seal device; 8 - static seal assembly; 81 - static ring; 82 - connecting pin; 83 - static ring seat; 84 - anti-rotation pin; 85 - static ring O-ring; 86 - static ring seat O-ring; 9 - dynamic seal assembly; 91 - dynamic ring seat; 92 - first dynamic ring O-ring; 93 - dynamic ring; 94 - second dynamic ring O-ring. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0040] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0041] It should be noted that like reference numerals and letters refer to like items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0042] In the description of the present invention, it should be noted that if terms such as "upper", "lower", "inner", "outer", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the figures, or the orientation or positional relationship in which the product of the present invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation on the present invention.

[0043] In addition, if terms such as "first", "second", etc. are used only for distinguishing descriptions, they cannot be construed as indicating or implying relative importance.

[0044] It should be noted that, without conflict, the features in the embodiments of the present invention can be combined with each other.

[0045] Please refer to Figure 1 , this embodiment provides a dry mechanical seal vacuum pump 100. The dry mechanical seal vacuum pump 100 includes a bearing 1, a rotor 2, an end cover 3, a dry mechanical seal device 7, a spring 4, a snap ring 5, and a throttle ring 6. The bearing 1, the end cover 3, and the dry mechanical seal device 7 are all sleeved on the end of the rotor 2, and the dry mechanical seal device 7 is clamped between the bearing 1 and the end cover 3.

[0046] The dry mechanical seal device 7 includes a dynamic ring seal assembly 9 and a static ring seal assembly 8. The dynamic ring seal assembly 9 is sleeved on the rotor 2 and rotates synchronously with the rotor 2. The static ring seal assembly 8 is connected to the end cover 3. The end faces of the dynamic ring seal assembly 9 and the static ring seal assembly 8 form a pair of friction pairs, with good sealing effect and very small leakage.

[0047] In this way, by adopting the dry mechanical seal device 7, it has a long service life and reduces the time cost of shutdown and maintenance; the dry mechanical seal device 7 has good high-temperature and corrosion resistance performance and is suitable for use in harsh vacuum pumps, significantly improving the use performance of the vacuum pump; the sealing contact surface is small, the friction between them is small, heat generation is reduced, and it has good sealing performance and a long service life; there is no need to use liquid as the liquid film of the sealing contact surface for sealing, avoiding liquid entering the cavity and damaging the process medium.

[0048] The spring 4 is clamped between the end cover 3 and the stationary ring seal assembly 8. The spring 4 is used to push the stationary ring seal assembly 8 towards the rotating ring seal assembly 9. In this way, by using the spring 4 to push the stationary ring seal assembly 8 towards the rotating ring seal assembly 9, it is ensured that the stationary ring seal assembly 8 and the rotating ring seal assembly 9 have a relatively large extrusion force, ensuring that the sealing performance of the sealing contact surface formed by the two is relatively good. The elastic force of the spring 4 on the stationary ring seal assembly 8 is: 25N - 30N. After repeated tests and calculations, when the spring 4 is maintained under an elastic force of 25N - 30N, it not only ensures that the sealing performance of the sealing contact surface is relatively good, but also ensures that the friction between the stationary ring seal assembly 8 and the rotating ring seal assembly 9 is moderate, and there will be no situation of overheating and damage too quickly.

[0049] Specifically, the stationary ring seal assembly 8 includes a stationary ring 81, a connecting pin 82, a stationary ring seat 83, an anti-rotation pin 84, a stationary ring O-ring 85 and a stationary ring seat O-ring 86. The end face of the stationary ring 81 and the end face of the rotating ring seal assembly 9 form a friction pair. The stationary ring 81 is connected to the stationary ring seat 83 through the connecting pin 82, and the stationary ring seat 83 is connected to the end cover 3 through the anti-rotation pin 84, so that the position of the stationary ring seat 83 relative to the end cover 3 is fixed, and the stationary ring seat 83 also plays a role in preventing the stationary ring 81 from rotating. In this way, the structural form of the stationary ring seal assembly 8 is simple and convenient for loading and unloading.

[0050] The end face of the stationary ring 81 for contacting the rotating ring seal assembly 9 is a circular ring, and the width of the circular ring is: 2mm - 2.5mm, preferably 2.2mm. In this way, the sealing contact surface is a circular ring with a width of: 2mm - 2.5mm, the sealing performance is relatively good, the friction is moderate, and there will be no situation of overheating and damage too quickly.

[0051] The stationary ring O-ring 85 is clamped between the stationary ring 81 and the stationary ring seat 83. The stationary ring O-ring 85 is a static seal. The stationary ring seat O-ring 86 is clamped between the stationary ring seat 83 and the end cover 3. The stationary ring seat O-ring 86 is a dynamic seal because under the pushing action of the spring 4, the stationary ring seat O-ring 86 will move slightly back and forth horizontally with the stationary ring seat 83. In this way, the stationary ring O-ring 85 can ensure the sealing ability between the stationary ring 81 and the stationary ring seat 83, and the stationary ring seat O-ring 86 can ensure the sealing ability between the stationary ring seat 83 and the end cover 3.

[0052] The dynamic ring sealing assembly 9 includes a dynamic ring seat 91 and a dynamic ring 93. The dynamic ring seat 91 is sleeved on the rotor 2, and the dynamic ring 93 is installed on the dynamic ring seat 91. The dynamic ring seat 91 plays a transmission role for the dynamic ring 93. The dynamic ring 93 forms a friction pair with the end face of the static ring sealing assembly 8. A first dynamic ring O-ring 92 is arranged between the outer circumference of the dynamic ring seat 91 and the inner circumference of the dynamic ring 93, and a second dynamic ring O-ring 94 is arranged between the end face of the dynamic ring seat 91 and the end face of the dynamic ring 93. The first dynamic ring O-ring 92 can ensure the verticality of the friction end face of the dynamic ring 93, so that the vertical face of the dynamic ring 93 is tightly fitted with the vertical face of the static ring 81, and the second dynamic ring O-ring 94 can ensure the sealing ability between the dynamic ring seat 91 and the dynamic ring 93. Moreover, the first dynamic ring O-ring 92 and the second dynamic ring O-ring 94 are both static seals.

[0053] The clamping ring 5 is clamped on the end cover 3, and the throttle ring 6 is in contact with the end cover 3 and the clamping ring 5, and is located on the periphery of the dynamic ring seal assembly 9. In this way, the throttle ring 6 is arranged between the end cover 3 and the dynamic ring seal assembly 9 to reduce the gap between the end cover 3 and the dynamic ring seal assembly 9, and prevent the lubricating oil of the bearing 1 from passing through the gap between the end cover 3 and the dynamic ring seal assembly 9, thereby affecting the working performance of the rotor 2. Moreover, the throttle ring 6 itself can also prevent the lubricating oil of the bearing 1 from passing over the dynamic ring seal assembly 9 to a certain extent.

[0054] The rotor 2 is provided with a first purge channel 21. Figure 1 The middle arrow indicates the direction of airflow. The inlet of the first purge channel 21 is located on the end face of the rotor 2, and the outlet of the first purge channel 21 is located on the outer peripheral surface of the rotor 2 and directly facing the dynamic ring seal assembly 9. The dynamic ring seal assembly 9 is provided with a through hole connected to the first purge channel 21, and the airflow is blown to the space between the dynamic ring seal assembly 9 and the static ring seal assembly 8 through the through hole. In this way, the airflow for purge, such as nitrogen, is blown into the first purge channel 21. After the nitrogen comes out, it enters the pump cavity and is pumped away and enters the atmosphere, so that the impurities between the dynamic ring seal assembly 9 and the static ring seal assembly 8 can be blown out of the pump body to ensure the stable operation of the internal parts.

[0055] The end cover 3 is provided with a second purge channel 31, the inlet of the second purge channel 31 is located on the outer surface of the end cover 3, and the outlet of the second purge channel 31 is located on the inner surface of the end cover 3. The airflow is blown toward the periphery of the dynamic ring seal assembly 9 through the second purge channel 31, and flows in a direction away from the static ring seal assembly 8, thereby preventing the lubricating oil on the bearing 1 from flowing toward the direction where the static ring seal assembly 8 is located. In this way, by blowing an airflow for purge, such as nitrogen, into the second purge channel 31, the airflow can be made to flow toward the direction where the bearing 1 is located, thereby preventing the lubricating oil on the bearing 1 from flowing toward the direction where the static ring seal assembly 8 is located.

[0056] In this embodiment, the material of the moving ring 93 can be selected as SSiC and doped with C, and the material of the stationary ring 81 can be selected as MMCG. The specific pressure of the spring 4 can be 0.06 - 0.1, preferably 0.08. In order to make the extrusion pressure between the moving ring 93 and the stationary ring 81 appropriate, the balance coefficient K between the moving ring 93 and the stationary ring 81 can be 0.6 - 0.65, and the sealing performance is stable.

[0057] Among them, the calculation formula of the balance coefficient K is:

[0058] K = D 1 2 squared - D 0 2 / D 1 2 -D 2 2

[0059] In the formula, D 1 is the outer diameter of the narrow ring, D 2 is the inner diameter of the narrow ring, D 0 is the balance diameter. The narrow ring thus understood refers to the circular end face of the stationary ring 81.

[0060] The beneficial effects of the dry mechanical seal vacuum pump 100 provided by the embodiment of the present invention include:

[0061] 1. The dry mechanical seal device 7 adopts the contact seal of the moving ring seal assembly 9 and the stationary ring seal assembly 8, with good sealing effect and very small leakage;

[0062] 2. Adopting the dry mechanical seal device 7 has a long service life and reduces the time cost of shutdown and maintenance;

[0063] 3. The dry mechanical seal device 7 has good high temperature and corrosion resistance, is suitable for use in harsh vacuum pumps, and significantly improves the performance of the vacuum pump;

[0064] 4. Adopting the dry mechanical seal device 7 can make the sealing contact surface smaller, the friction between them smaller, reduce heat generation, and has good sealing performance and a long service life;

[0065] 5. There is no need to use liquid as the liquid film of the sealing contact surface for sealing, which avoids the liquid entering the cavity and damaging the process medium. At the same time, it avoids the dust in the pump cavity entering the bearing box and damaging the bearing.

[0066] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A dry mechanical seal vacuum pump, characterized in that, the dry mechanical seal vacuum pump includes a bearing (1), a rotor (2), an end cover (3) and a dry mechanical seal device (7). The bearing (1), the end cover (3) and the dry mechanical seal device (7) are all sleeved on the end of the rotor (2), and the dry mechanical seal device (7) is clamped between the bearing (1) and the end cover (3); the dry mechanical seal device (7) includes a moving ring seal assembly (9) and a stationary ring seal assembly (8). The moving ring seal assembly (9) is sleeved on the rotor (2) and rotates synchronously with the rotor (2). The stationary ring seal assembly (8) is connected to the end cover (3), and the end faces of the moving ring seal assembly (9) and the stationary ring seal assembly (8) form a pair of friction pairs; a first purge channel (21) is provided on the rotor (2). The inlet of the first purge channel (21) is located on the end face of the rotor (2), and the outlet of the first purge channel (21) is located on the outer peripheral surface of the rotor (2) and faces the moving ring seal assembly (9). A through hole communicating with the first purge channel (21) is provided on the moving ring seal assembly (9), and air flow blows through the through hole into the space between the moving ring seal assembly (9) and the stationary ring seal assembly (8); a second purge channel (31) is provided on the end cover (3). The inlet of the second purge channel (31) is located on the outer surface of the end cover (3), and the outlet of the second purge channel (31) is located on the inner surface of the end cover (3). Air flow blows through the second purge channel (31) to the periphery of the moving ring seal assembly (9) and flows in a direction away from the stationary ring seal assembly (8), preventing the lubricating oil on the bearing (1) from flowing towards the direction where the stationary ring seal assembly (8) is located.

2. The dry mechanical seal vacuum pump according to claim 1, characterized in that, the dry mechanical seal vacuum pump further includes a spring (4). The spring (4) is clamped between the end cover (3) and the stationary ring seal assembly (8), and the spring (4) is used to push the stationary ring seal assembly (8) towards the moving ring seal assembly (9).

3. The dry mechanical seal vacuum pump according to claim 2, characterized in that, the elastic force of the spring (4) on the stationary ring seal assembly (8) is: 25 N to 30 N.

4. The dry mechanical seal vacuum pump according to claim 1, characterized in that, the stationary ring seal assembly (8) includes a stationary ring (81), a connecting pin (82), a stationary ring seat (83) and an anti-rotation pin (84). The end face of the stationary ring (81) and the end face of the moving ring seal assembly (9) form the friction pair. The stationary ring (81) is connected to the stationary ring seat (83) through the connecting pin (82), and the stationary ring seat (83) is connected to the end cover (3) through the anti-rotation pin (84).

5. The dry mechanical seal vacuum pump according to claim 4, characterized in that, The end face of the stationary ring assembly (81) for contacting the dynamic ring seal assembly (9) is a circular ring, and the width of the circular ring is: 2 mm to 2.5 mm.

6. The dry mechanical seal vacuum pump according to claim 4, wherein, The stationary ring seal assembly (8) further includes a stationary ring O-ring (85) and a stationary seat O-ring (86). The stationary ring O-ring (85) is clamped between the stationary ring assembly (81) and the stationary seat (83), and the stationary seat O-ring (86) is clamped between the stationary seat (83) and the end cover (3).

7. The dry mechanical seal vacuum pump according to claim 1, wherein, The dynamic ring seal assembly (9) includes a dynamic ring seat (91) and a dynamic ring assembly (93). The dynamic ring seat (91) is sleeved on the rotor (2), and the dynamic ring assembly (93) is installed on the dynamic ring seat (91). The dynamic ring assembly (93) and the end face of the stationary ring seal assembly (8) form the friction pair. A first dynamic ring O-ring (92) is arranged between the outer peripheral surface of the dynamic ring seat (91) and the inner peripheral surface of the dynamic ring assembly (93), and a second dynamic ring O-ring (94) is arranged between the end face of the dynamic ring seat (91) and the end face of the dynamic ring assembly (93).

8. The dry mechanical seal vacuum pump according to claim 1, wherein, The dry mechanical seal vacuum pump further includes a snap ring (5) and a throttle ring (6). The snap ring (5) is clamped on the end cover (3), and the throttle ring (6) abuts against the end cover (3) and the snap ring (5) and is located outside the dynamic ring seal assembly (9).

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